If you thought that you don't like Anselm's argument, you are in good company. Many famous thinkers found it unsatisfactory and tried to explain what is wrong with it.
P. Strawson, a contemporary philosopher, objected to Anselm's Ontological Argument for God's Existence. Here is the main point Strawson makes, which allows him to show that Anselm's argument is faulty: "To form a concept, however rich, is one thing; to declare it instantiated is another. Logical or analytical necessity relates solely to the connection of concepts with one another. No concept can logically guarantee its own instantiation in something [that is] not itself a concept." ['instantiation' means that, after I have thought of something in my mind, I can also find something that exists in reality and "is" this thing, or corresponds to this thing of which I thought.]
Another famous philosopher, Kant, also disapproved of Anselm's Argument. This is what he had to say: "In whatever manner the understanding may have arrived at a concept, the existence of its object is never, by any process of analysis, discoverable within it; for the knowledge of the existence of the object consists precisely in the fact that the object is posited in itself, beyond the (mere) thought of it" (Critique of Pure Reason, B667, trans. Kemp Smith) In class, we will discuss what he means by this.
A key point is this: Is 'existence' a property or quality of things? For instance, is 'existence' like size or color? [A thing is red, means that this thing has the quality red; similarly, a thing can have the property of being small or large. Is existence like this? Can you see how this is key for Anselm's argument?
Here is another objection, which Kant also thought of - paraphrased: I can think of a thousand-pack of beers. This does not mean that a thousand-pack exists - no beer company has even attempted this prodigious feat. All I can do is say: My thought that there is a thousand-pack of beers exists in my mind. This does not tell me anything I don't know already. Obviously, this thought exists in my mind - I just told you about it. But it exists as a thought, not as a real thing. To go from the thought in my mind [the 'thousand-pack'] to a thousand-pack that exists in reality, I must be able to do something more than think about the thousand-pack. I must be able to produce the thousand-pack in front of you. Now, notice this: even if I produced the thousand-pack in front of you - by some miracle - the concept in my mind of a thousand-pack would not be affected; my thinking of a thousand-pack would not become thinking of a thousand-and-one-pack. This tells me something: That concepts [the 'thousand-pack' in my mind] cannot, by themselves, do the trick of giving information about real existence. It is true that a concept exists in my mind, but for the OBJECT of this concept to exist in reality, one more real fact - the actual existence of the object - needs to be added.
Could the problem with Anselm's argument lie in his understanding of "perfection?" Notice what is key for his argument: "God" is that than which we cannot ever conceive anything greater. Could this be impossible for the human mind? In other words, could it be that you can always conceive of something greater than the greatest thing you have conceived. For instance, in the case of numbers, no matter how great a number n is, you can always think of n+1.
Can we help St. Anselm out? Could it be that the case of God is different from all other cases which we know from experience? How would this strengthen Anselm's position?
Thomas Aquinas, known to the Middle Ages as the “Angelic Doctor”, did not accept Anselm’s Ontological Proof, either. It seems that Aquinas took Anselm’s deeper claim to be this: God’s existence is self-evident. But there are problems with this: 1. If it is self-evident, then it does not really need to be proven. Maybe, Anselm himself did not think of his Argument as a Proof – at least not in the way we would think of a Proof. 2. To say that God’s existence is self-evident we must be thinking of, and talking to, faithful believers of a religion that defines God in a certain way. For instance, if someone is a pagan who thinks that gods were themselves generated or born, though they are immortal, then this pagan faithful does not think of God as necessarily existent – obviously, there was a time when a god had not been born yet, for a pagan believer. Obviously, if a philosopher proved to you that a God with certain qualities exists, then you would be foolish not to accept that this God exists. But, notice that the proofs you are reading assume that God has certain qualities -- they take them for granted; and, taking these qualities for granted actually assists with proving that God exists! [Check Anselm's argument again, if you have any doubts.] 3. It gets worse. Suppose you are a believer of a religion that defines God in such a way that you cannot think of God without thinking of God as something that necessarily exists. [Notice that this is, more or less, the crux of Anselm’s argument.] In that case, the statement ‘God exists’ is for you analytical: that He exists is already, in some way, contained in your concept of ‘God.’ How does this work? Because, for instance, you can say, with Anselm, that God is that than which nothing greater can be thought. This is your definition of God. There is no difference, for you, between ‘God’ and ‘that than which nothing greater can be thought.’ If there is no difference, then you don’t learn anything new by taking the first step of Anselm’s argument. If you don’t learn anything new, then how exactly are you proving anything? But, there is even one more problem. For many religions – Judaism, Christianity, and Islam – you cannot really comprehend ‘God.’ So, you cannot really comprehend ‘that than which nothing greater exists.’ This makes the prospects for a Proof even dimmer.
Aquinas also levels against Anselm the more obvious objection: It does not follow that something exists in actuality only because someone understands something – because it exists IN ONE’S MIND. See Kant’s similar objections, above.
Aquinas also finds poor Anselm’s argument CIRCULAR. For Anselm to be able to demonstrate God’s existence this way, we should first grant him what he is trying to prove: that the “thing than which nothing greater can be thought to exist” exists! [Is Aquinas fair to Anselm here?]
What if we define God as Truth? [Maybe, Anselm went wrong because he focused on the concept of God as “that than which nothing greater can be thought to exist.” What if we focus, instead, on God as the Truth? Aquinas sees this as a better chance. Can we say that there is no Truth? Aquinas thinks that the answer is no: Even if we say that “there is no truth,” still we are admitting the statement “there is no truth” as the truth! So, there is at least one thing that we hold as the truth. [Notice the same confusion here: We are talking of truth in the mind, aren’t we? How exactly are we going to move from this to Truth as the existing, living God?] [By the way, see the Puzzles and Paradoxes at the end of your book that deal with truth. Analytical philosophers are more apt to say that sentences like “this statement is not true” are nonsensical. See how this defeats Aquinas’ purpose.] Aquinas does not think that we can prove God’s existence by starting from a notion of God as the Truth. Aquinas puts it this way: It is evident to us that there is truth, but the existence of a Primal Truth [God] is not self-evident. After all, we are unable to comprehend the essence of God in the first place.
Another philosophical genius, Duns Scotus, known as the “Subtle Doctor,” pointed out another related problem. God is also supposed to be simple – for certain religions. This means that God has no parts: if He had parts, God could change by reshuffling those parts; but God cannot change: What would God change to? To something less perfect than what He is already? That’s absurd. Or would He change to something more perfect than what He is? But, in that case, why did He wait to do this? How could God be les perfect than the most perfect thing? So, God cannot change; God has no parts; God is simple. Though we cannot comprehend God’s essence, who can, at least, grasp what God is not: God is not – cannot be – complex; God must be simple. In that case, though, God’s Essence and God’s Essence must be one and the same thing. [Notice that we don’t have to be able to understand what His Essence is; only that it cannot be different from His Existence – because, in that case, God would not be simple – God would be described by two different characteristics – that He has an Essence and that He exists.] So, in God’s case, His Essence is the same as His Existence. There is no other thing about which this can be true. In a sense, this makes Anselm’s point in a different way: To think of God [Essence] is to think of something that necessarily Exists [=Existence]. But, notice what else this means: We limited human beings understand things by breaking them down – by saying that a is b; so, I now understand a, which I did not know before, because I see that a is b – and let’s assume that I already knew what b is. But how are we going to do this with God, since there is no difference between any a and any b we can think of trying to describe God? [God is simple, remember.] This means that we cannot really prove that “God exists.” We cannot start with “God” and then move to “God, and He exists.” That “and” is the problem – there is no separate thing – existence – we can subtract from and add to the notion ‘God,’ because ‘God’ corresponds to a simple thing. It follows that the proposition ‘God exists’ can only be grasped by Intuition – not through logical demonstration. This was Duns Scotus’ point.
See more comments on this, under God’s Existence.
The Text of the Ontological Argument on Line
Critiques of Anselm's Ontological Argument